from WorldMysteries Website

A DNA molecule consists of a ladder, formed of sugars and phosphates, and four nucleotide bases:

• adenine  (A)

• thymine  (T)

• cytosine (C)

• guanine  (G)

The genetic code is specified by the order of the nucleotide bases, and each gene possesses a unique sequence of base pairs. Scientists use these base sequences to locate the position of genes on chromosomes and to construct a map of the entire human genome.

The Human Genome Project (HGP) is an international research program designed to construct detailed genetic and physical maps of the human genome, to determine the complete nucleotide sequence of human DNA, to localize the estimated 50,000-100,000 genes within the human genome, and to perform similar analyses on the genomes of several other organisms used extensively in research laboratories as model systems.

The scientific products of the HGP will comprise a resource of detailed information about the structure, organization and function of human DNA, information that constitutes the basic set of inherited "instructions" for the development and functioning of a human being. Successfully accomplishing these ambitious goals will demand the development of a variety of new technologies.

It will also necessitate advanced means of making the information widely available to scientists, physicians, and others in order that the results may be rapidly used for the public good. Improved technology for biomedical research will thus be another important product of the HGP. From the inception of the HGP, it was clearly recognized that acquisition and use of such genetic knowledge would have momentous implications for both individuals and society and would pose a number of policy choices for public and professional deliberation.

Analysis of the ethical, legal, and social implications of genetic knowledge, and the development of policy options for public consideration are therefore yet another major component of the human genome research effort.

The Human Genome project revealed that human beings have 30,000-40,000 genes. That number is much lower than expected. For example, fruit fly has 13,300 genes, roundworm - 18,300 genes, mustard weed - 25,700 genes.

According to genetic analysis, though, more than 98% of human DNA is identical to chimpanzee DNA. In fact, chimpanzees are more closely related to humans than orangutans and gorillas. "Humans are simply odd looking apes," psychologist Roger Fouts of Central Washington University in Ellensburg, Washington, writes in his 1997 book, Next of Kin: My Conversations With Chimpanzees.

"A traveler from an antique land... lives within us all," claims Sykes, a professor of genetics at Oxford. This unique traveler is mitochondrial DNA, and, as this provocative account illustrates, it can help scientists and archeologists piece together the history of the human race. Find out more by reading this book: The Seven Daughters of Eve: The Science That Reveals Our Genetic Ancestry by Bryan Sykes.
 

Controversial Discoveries

Several years ago, spearpoints and other tools of modern man were found under a layer of volcanic ash. When Dr. McIntyre, a member of the U.S. Geological Survey, was invited to date the overlying ash, the archaeologists thought it could be as old as 20,000 years old, pushing the arrival of man in the New World back around 5,000 years.

No one was prepared when uranium series dating and fission tracking methods provided the astounding age of 250,000 years. Dr. McIntyre shares what happened next:

"I thought, okay, we got something big here but I'm going to stick with the dates. I didn't realize it was going to ruin my whole career."

Tree of Life
 

Mesopotamian "Tree of Life"


The Olmec "Tree of Life" (Mesoamerican Cosmology).
The lineage founder, 2 Grass, is being born from a twisting World Tree.

Detail from Selden Codex page 2. Source: FAMSI
 

DNA - our modern "Tree of Life"
 

The Human Genome Project
Summary of the Initial Sequencing and Analysis of the Human Genome

from WhiteHeadInstitute Website

recovered through WayBackMachine Website

Over the last decade, genomes have been sequenced for more than 40 species, mostly bacteria. The human genome sequence is 8 times larger than all the previously sequenced genomes put together. In 1990, the Human Genome Project (HGP) began as an international collaboration propelled by the hope that global views of entire genomes would allow researchers to attack scientific problems in systematic and unbiased ways. In its early years, the HGP produced maps of the human and mouse genomes and sequenced the genomes of yeast and nematode worm.

Now, it has produced a 94%-complete working draft of the human genome sequence, the totality of human DNA, where each letter in the draft has been read an average of 5 times. About 30% of the human genome has been sequenced with more than twice this redundancy, resulting in highly accurate "finished" sequence.

For example, the whole of chromosomes 21 and 22 have been sequenced to a finished state. No later than 2003, all the human chromosomes will be sequenced to a finished state.

The Human Genome Project first separated the genome into large "clones" — segments of DNA each representing about 0.005% of the whole genome — before chopping the clones and sequencing small fragments. Using such clones whose positions are known added to the confidence that the genome sequence would be assembled properly and allowed effective international collaboration.

All collaborators in the project made sequence data publicly available without restriction within 24 hours. Large blocks of highly repetitive sequence, for example at the tips of chromosome arms and at the centromeres (the portions of chromosomes that appear as pinched centers when chromosomes are condensed) have been avoided, because current technology cannot yet sequence these regions.

The total human genome, contained in a set of 23 chromosomes, is now estimated to contain 3,164.7 million letters (or nucleotides). Genome size does not always correlate with the apparent complexity of a species because of the large amounts of repetitive sequence in many genomes. In humans the actual part of the genome that codes for proteins makes up less than 2% of the genome while repeated sequences make up at least 50% of the genome.

Repetitive sequences are thought to have no direct functions, but they shed light on chromosome structure and dynamics. They hold important clues about evolutionary events, help chart mutation rates, and by seeding DNA rearrangements, they can modify genes and create new ones. They also serve as tools for genetic studies.

The vast majority of repeated sequences in the human genome are derived from transposable elements — sequences like those that form viral genomes — that propagate by inserting fresh copies of themselves in random places in the genome. A full 45% of the human genome derives from such transposons. A major surprise of this new global analysis of the human genome is that many components in this diverse array of repeated sequences, traditionally considered to be "junk," appear to have played a beneficial role over the course of human evolution.

Genes are sprawled over much larger regions in humans compared with fruit fly and nematode worm. Genes remain difficult to identify in humans because they form such a small portion of the genome and are so spread out, but it appears that the total number of genes is 30,000-35,000, close to the number originally estimated some 20 years ago, but much smaller than more recent estimates.

Apparently, humans have only twice as many genes as the fly or worm, but they have on average three times as many kinds of proteins because of "alternative splicing," a process that can yield different protein products from the same gene.

Compared with the organisms whose genomes have been sequenced before, humans have a particular abundance of proteins involved in cell structure, defense and immunity, DNA copying, the synthesis of RNA and proteins, and communication between cells. Humans have an unusually high number of complex proteins that fit into more than one functional category and many proteins that are embedded in the surface of cells.

Since the genome sequence has been released as it was generated over the last four years, a large number of discoveries have already been spawned by the sequence data. At least 30 different disease genes have been identified by directly using sequence produced by the HGP. In the coming years, the human genome should be sequenced to a finished state, where all gaps are closed and the sequence is at least 99.99% accurate.

Genome sequence from other species will provide crucial insights about genes and the regions that regulate their activity. There will be a pressing need for improved methods to analyze the abundance of information being generated. And genetics will become an increasingly important part of the medical mainstream.

The pressure will grow to encourage educated use of genetic information and to set thoughtful limits on its use.